UM Study: Too Much of a Good Thing Can Be Bad for Corals

October 22, 2012 — A new study by scientists at the University of Miami's Rosenstiel School of Marine and Atmospheric Science shows that corals may be more severely impacted by climate warming when they contain too many symbiotic algae. The single-celled algae living inside corals are usually the key to coral success, providing the energy needed to build massive reef frameworks. However, when temperatures become too warm, these algae are expelled from corals during episodes of coral bleaching that can lead to widespread death of corals. Until now, it was thought that corals with more algal symbionts would be more tolerant of bleaching because they had more symbionts to lose. The new study shows that the opposite is true. The article, " Excess algal symbionts increase the susceptibility of reef corals to bleaching ," appears in the online. "We discovered that the more symbiotic algae a coral has, the more severely it bleaches, showing that too much of a good thing can actually be bad," said Ross Cunning, student and lead author of the study.